1. Field of the Invention
The present invention relates to the control system of an inserter system, and more particularly, to a control system that operates the inserter chassis at a dynamic speed in dependence upon the document input rate for the inserter system.
2. Discussion of the Prior Art
The term "mailpieces" as used herein means items intended to be delivered by a postal service or private courier service. Typically preparation of mailpieces includes, but is not limited to, printing or otherwise providing documents including variable information pertaining to addressees of the mailpieces and the assembly of such documents with other elements of the mailpiece. The term "assembly" as used herein means the execution of actions to incorporate the documents into mailpieces. Typically, such actions can include: accumulating documents with other materials such as preprinted inserts, folding and inserting the resulting accumulations into envelopes, printing addresses and other information on the outside of the envelopes, and franking the mailpiece with an appropriate postage amount.
Inserter systems for the assembly of mailpieces are well known. A typical inserter system is shown in FIG. 1. Inserter system 10 includes burster/feeder 12 which inputs preprinted documents in fanfold form, separates the documents and removes and discards sprocket feed strips FS from the edges of the document. Each group of documents for a particular mailpiece includes at least one control document CD. On control documents CD strips FS are marked with code BC which is read by scanner 14 before strips FS are removed. In simpler systems code BC can be a "dash code" of the type known for use in directly controlling inserter systems. In newer, more complex systems code BC can be a conventional bar code which serves as a pointer to a mailpiece record which record contains information for controlling the inserter; as will be more fully described below. In other known inserter systems, the documents can be in cut sheet form and a cut sheet feeder can be used in place of burster/feeder 12.
Control document CD, and any additional associated pages are fed from burster feeder 12 to accumulator 16 where documents for each mailpiece are formed into separate accumulations A and folded.
Accumulation A is then fed to insert stations 20A and 20B where preprinted inserts I are added to form accumulations A1 and A2. Those skilled in the art will of course recognize that the number of such insert stations used will vary from application to application.
Accumulation A2 is then fed to insert station 22 where it is inserted into an envelope and sealed to form mailpiece MP.
Mailpiece MP is then fed to address printer 24 which prints address AD on the outside of the envelope. Depending on the size of the print field of printer 24, printer 24 also can be used to print other information such as a variable return address (or other text message) RA, logo L, and postal barcode PBC on the envelope. (Those skilled in the art will recognize that dash codes as described above typically cannot include sufficient information to define even address AD so that systems incorporating dash codes typically use window envelopes to provide addressing information.)
System 10 also includes out stacker 30 for diverting mailpieces when an error is detected.
As noted above inserter systems wherein said code BC is a barcode which is used as a pointer to a mailpiece record (i.e. an electronic record associated with a mailpiece to be assembled) are known. By incorporating data for controlling assembly of mailpieces in mailpiece records an essentially unlimited amount of data can be associated with each mailpiece. Thus addresses, return addresses, logos, and postal bar codes can all readily be specified in addition to specification of the number of inserts to be added at each insert feeder, postage amounts, etc. Systems incorporating such mailpiece records are described in commonly assigned U.S. Pat. No. 4,800,505; to: Axelrod et al.; for: Mail Preparation System; issued Jan. 24, 1989, which is hereby incorporated by reference. Embodiments of the system of U.S. Pat. No. 4,800,505 are marketed by the assignee of the present application under the name "Direct Connection", described in The Direct Connection, version 1.30.
While systems such as those described above have proven highly successful certain disadvantages remain. In particular the fact that chassis cycles at fixed intervals while documents are delivered at varying intervals means that a potential exists that no documents will be available for a particular cycle. Clearly the possibility of such "dry holes" can be eliminated simply by operating the chassis slowly enough to assure that the maximum number of sheets can be accumulated in one cycle but, equally clearly, operating at that minimal speed will be highly inefficient in the general case where relatively few accumulations with a maximum number of sheets are expected. Conversely, in mailing jobs having a relatively large number of large accumulations, running too fast will cause a large number of dry holes and a higher throughput is achieved by operating the chassis at a slower speed. This problem is exacerbated by the fact that accumulation size will vary with within mailing jobs.
Heretofore efforts to improve the operating efficiency of inserter systems have not addressed this problem in a direct, simple and cost effective manner. Thus, U.S. Pat. Nos. 4,987,547 and 5,083,281; to: Rabindran et al. teach a method for optimizing system speed to minimize time lost to jams and stoppages; while U.S. Pat. No. 5,826,869; to: Nyffenegger teaches a non-standard, buffered, variable speed document feeder which it is believed would substantially add to the cost and complexity of an inserter system.
Thus it is an object of the subject invention to provide a simple, cost-effective method for tuning the performance of an inserter system during the run-time of a mailing job.